CWE-338 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
- Abstraction:Base
- Structure:Simple
- Status:Draft
- Release Date:2006-07-19
- Latest Modification Date:2023-10-26
Weakness Name
Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Description
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.
When a non-cryptographic PRNG is used in a cryptographic context, it can expose the cryptography to certain types of attacks. Often a pseudo-random number generator (PRNG) is not designed for cryptography. Sometimes a mediocre source of randomness is sufficient or preferable for algorithms that use random numbers. Weak generators generally take less processing power and/or do not use the precious, finite, entropy sources on a system. While such PRNGs might have very useful features, these same features could be used to break the cryptography.
Common Consequences
Scope: Access Control
Impact: Bypass Protection Mechanism
Notes: If a PRNG is used for authentication and authorization, such as a session ID or a seed for generating a cryptographic key, then an attacker may be able to easily guess the ID or cryptographic key and gain access to restricted functionality.